diff --git a/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp b/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp
index 09c248342e..518bd26fd7 100644
--- a/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp
+++ b/libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp
@@ -138,5 +138,5 @@ void AP_WheelEncoder_Quadrature::irq_handler(uint8_t pin,
     update_phase_and_error_count();
 
     // record update time
-    irq_state.last_reading_ms = timestamp;
+    irq_state.last_reading_ms = timestamp * 1e-3f;
 }